1. Field of the Invention
The present invention relates to a bearing structure for miniature electric motors suitable for use in automotive electric devices.
2. Description of the Related Art
A known miniature motor of the kind mentioned above has a gear such as a worm gear integrated with the motor output shaft so that the output of the motor is transmitted to the driven side of the motor at a reduced speed.
Conventionally, mounting of the gear such as the worm gear to the motor shaft is conducted by forcibly fitting the gear to an end of the motor shaft projecting from a front frame of the assembled motor. In this conventional embodiment, the gear cannot be withdrawn from the motor shaft once the gear is press-fitted to the motor shaft. This inconveniently prohibits various operations such as renewal of the armature core. In addition, the presence of the motor frame hampers the performance of press-fitting the gear. Furthermore, the motor shaft has to be gripped at a position remote from the motor frame, i.e., at a portion near the free end thereof, in order to avoid interference with the motor frame, so that only the extreme end portion of the motor shaft is available as the portion to which the gear is to be fitted. Consequently, the position of the gear is too largely spaced from the front frame which supports the motor shaft, which undesirably enhances the cantilever-type posture of the motor shaft carrying the gear, thus posing various disadvantages from the viewpoint of construction of the mechanism.